Investigations of regularities in the accumulation of hydrogen-reduced slags in circulation circuits with lead-containing coolants

The paper presents a computational analysis of regularities in the accumulation of slags during the interaction of lead and lead-bismuth coolants with oxygen gas. Oxidation of lead-containing coolants will cause the formation of lead oxide, while the formation of bismuth oxide is unlikely. Dosed supply of oxidizing gas to lead-containing coolants makes it possible to oxidize, selectively, chromium and nickel to their oxides without the slag formation from solid lead oxide. Regularities were studied which are involved in the lead oxide formation during the interaction of lead-containing coolants with oxygen gas. It has been found that, in the process of interacting with oxygen gas, a lead-bismuth alloy is oxidized 1.7 times as intensively as lead, this being explained by the presence of bismuth in the alloy. Bismuth is oxidized more intensively than both lead and the lead-bismuth alloy. The inert gas overpressure during depressurization does not prevent air oxygen from entering the circuit, and the dependence of the nitrogen and oxygen flow into the circuit on the argon flow out of the loop is close to linear regardless of the circuit state (cold, without coolant; heated, without coolant; heated, with circulating coolant). Oxygen is a chemically active impurity and is absorbed by the circuit; it is therefore important to control nitrogen in the gas spaces of the reactor and research plant circuits with lead-containing coolants. This will make it possible to signal, in a timely manner, the ingress of oxygen into the circuit and to take measures required to avoid or reduce the scale of the slag formation from lead oxides.

Non-invasive Optical Technical Identification of Red Pigments on Chinese Paper Notes

Red pigments with bright colors were widely used in ancient Chinese painted pottery, books, antiques, calligraphy, and paintings. Herein, red pigments of traditional paper notes were investigated by non-invasive optical technology in order to enrich the Chinese historical pigments knowledge base. The results of laser Raman spectroscopy tests on five paper notes clearly identified the inorganic mineral pigments including ocher and cinnabar. Infrared spectroscopy measurements indicated that an artificial synthetic magenta was employed as the organic pigment. Inorganic and organic red pigments were applied together on the same samples 2 and 5 which can be speculated to serve an anti-counterfeiting function. In addition, SEM-EDS analysis of sample 5 clearly showed that the red pigment was composed of lead oxides and ZnS was added as color modulator. Combined with the abovementioned non-invasive techniques, analysis of printed pigments can provide a feasible method to authenticate and conserve paper notes.

Complex processing of tin-lead dross into solders and ligatures

The use of industrial waste is one of the main problems of the modern economy. In Belarus, there is no primary metallurgical processing of natural raw materials, so the use of secondary materials and production waste is a very relevant and important task for the industry, given into account that the cost of metals extracted from secondary raw materials is several times less than the primary ones.One of the types of such raw materials is tin-lead dross (ash), which consists of tin and lead oxides with inclusions of the metal component beads. The most valuable element in dross is tin, the price of which is much higher than the cost of many non-ferrous metals. The aim of the work was to study the influence of various technological factors on the metallurgical output during the processing of tin-lead ash into solders and ligatures.In this regard the results of previous studies related to the extraction of tin and lead in the processing of secondary raw materials were summarized, and new data on technological methods for deeper metallurgical processing of dross (ash) were presented. This allowed them to develop options for obtaining high-quality solder type POS 61 and ligatures.

Elaboration and Mechanical-Electrochemical Characterisation of Open Cell Antimonial-lead Foams Made by the “Excess Salt Replication Method” for Eventual Applications in Lead-acid Batteries Manufacturing

In this study, open cell 25 % antimony-lead alloy foams are fabricated for possible use to lighten thick plates of lead-acid batteries. A new inexpensive and simple variant of the salt replication process is developed and explored. Different morphology and shapes have been successfully obtained with “excess salt replication” method (abbreviated as ESR method). Best porosity of about 68 % is obtained with salt particles size of about 3 mm. SEM and EDXS investigation of the composite salt/antimony alloy before NaCl leaching revealed the presence of the lead oxides microfilm coating cell walls and becoming lead carbonates after salt removal. Uniaxial compressive behaviour of the resulting cellular materials is studied for foams with porosities between 45 % and 70 %, and salt grain size ranging between 2.5 and 5 mm. A higher plateau stress is reached compared to the results obtained in the literature working on the aluminium foams. The reproducibility of the process is proved along samples.

Composition and texture of a set of marvered glass vessels from 12th century ad Branicevo, Serbia

Strongly coloured glass vessels decorated with marvered threads of white glass are a wide-spread and popular, but rarely studied group of high-quality glassware of medieval Islamic origin. Relatively little is known about the composition and production places of these vessels, and their chronological range is not very well defined, as many of the published finds lack contextual evidence. Here, we present detailed chemical and microstructural data on a set of well-dated purple glass vessels decorated with white threads, excavated at the Mali Grad site in Branicevo, Serbia, in an archaeological context dated to the middle/second half of the 12th century AD. The set comprises at least sixteen different vessels, manufactured from two different batches of probably Levantine plant-ash glass coloured by manganese oxide. Significantly, the results demonstrate that these batches are correlated to particular vessel shapes. The base glass of the white threads is comparable to that of the purple vessel glass, but instead of being coloured by added manganese oxide, it contains considerable amounts of tin and lead oxides which provide the effect of opacity and white colour. No difference in composition can be seen between the white glass threads used to decorate the vessels from the two different manganese-coloured batches, thus indicating a likely common production origin of the whole set.

Lead Corrosion and Formation of Lead Oxides from a Lead-air Cell in Methanesulfonic Acid

The corrosion of lead in methanesulfonic acid solution in the presence of a MnO2 air cathode in a primary lead-air cell is in-vestigated. The highest power density of the lead-air cell is 2.8 mW cm-2. X-ray photoelectron spectroscopy and powder X-ray diffraction results demonstrate the formation of lead (II) oxide and lead (IV) dioxide on the air cathode after continuous discharge. Field emission scanning electron microscopy image shows that the surface coverage of lead (II) oxide and lead (IV) dioxide on the air cathode is only partial and will allow oxygen reduction.